Antigenic Expression of Neuron-Associated Class III Beta-Tubulin Isotype (hβ4) and Microtubule-Associated Protein 2 (MAP2) by the Human Retinoblastoma Cell Line WERI-Rbl

The antigenic expression of two neuron-associated microtubule proteins, class III β-tubulin isotype (hβ4) and microtubule-associated protein 2 (MAP2), was evaluated in a comparative immunoblot and immunocytochemical study of the human retinoblastoma cell line WERI-Rbl maintained for up to 30 days in three different in vitro conditions. Western blots were performed on whole sodium dodecyl sulfate extracts of cells grown in floating suspensions, on Gelfoam matrices and on coverslips. Immunoperoxidase histochemistry was performed on matrix cultures. Immunoblotting demonstrated that hβ4 and MAP2 were present under all culture conditions. By immunocytochemistry, staining of cytologically undifferentiated cells with anti-hβ4 and anti-MAP2 monoclonal antibodies was found on Gelfoam matrix explants. In contrast, glial fibrillary acidic protein was not detected by either immunoblots or immunocytochemistry. These findings are in keeping with the solely neuroblastic nature of this line and provide no evidence for its divergent (i.e. neuronal and glial) differentiation capacity.